IEEE Electrification Magazine - September 2014 - 44
Train Moving Direction
Station 1
1
Station 2
2
3
-
Traction
Transformer
Accelerating Region
2
Constant Speed Region
3
Regenerative Braking Region
Electric Energy Flow Direction
=
dc/ac
Inverter
1
~
+ Third Rail
Low-Voltage Grid
High-Voltage Grid
Figure 10. The electric energy flow diagram of a train system.
shown in Figure 12, in which the voltage loop is the outer
loop and the current loop is the inner loop. In three-phase
rotating coordinates, the inverter system contains timevarying components, which render the design of control
systems rather difficult. Hence, the three-phase abc system
is converted to the dq rotating two-phase system.
In the inner loop, the proportional component of the
proportional integral (PI) regulator G i would increase the
damping coefficient for stability purposes. The integration
component of G i is used to reduce the steady-state error
of the current loop. In the outer loop, the G v of the PI regulator would make the output voltage follow the reference
voltage. This dual closed loop system responds fast with a
small static error. The addition of feed-forward compensation for load disturbances would improve the robustness,
as the load current-which is subject to the outer disturbance signal-lies outside the current inner loop.
Economic Merits of Regenerative Braking
Table 1 shows the timetable for the Metro line 13 at the Wudaokou station in Beijing, China. In this table, trains will be arriv-
ud
2
T1
T3
D1
T5
D3
D5
A
P
ud
2
B
C
T2
T4
D2
u0a
u0b
i1a
i1b
u0c
i1c
L
u0a
u0b
u0c
D6
P1
Figure 11. The inverter circuit for the dual control system.
44
I E E E E l e c t r i f i c ati o n M agaz ine / september 2014
i0a
i0b
i0c
ZL
C
T6
D4
r
ing at the station every 6-7 min between 5:19 and 6:20 h. The
interval time depends on the time of the day and the day of
the week, and the average interval time on weekdays is
5.2 min. Accordingly, 420 trains pass through the Wudaokou
station with a daily regenerative braking energy of 420 #
16.53 = 6,942.6 kWh (see motor.ece.iit.edu/data/train.doc for
more information). For weekends, the average train interval
time is 8.3 min, the number of trains is 262, and the total
regenerative braking energy is 262 # 16.53 = 4,330.86 kWh. The
monthly (including four weeks + two weekdays) regenerative braking energy is (6,942.6 # 5 + 4,330.86 # 2) # 4 +
6,942.6 # 2 = 187,384 kWh. The annual regenerative braking
energy is 187,384.08 # 12 = 2,248,608.96 kWh. If the electricity
is priced at US$0.1/kWh, the annual saving at Wudaokou
station is around US$0.225 million. The annual savings for
the 16 stations along the Metro line 13 is US$ 0.225 # 16 =
3.6 million annually.
For the months with air-conditioning loads (June
through September), the monthly average energy consumption of Metro line 13 at each station is 7.64 # 104 kWh. For
non-air conditioning months (October through May), the
http://motor.ece.iit.edu/data/train.doc
Table of Contents for the Digital Edition of IEEE Electrification Magazine - September 2014
IEEE Electrification Magazine - September 2014 - Cover1
IEEE Electrification Magazine - September 2014 - Cover2
IEEE Electrification Magazine - September 2014 - 1
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IEEE Electrification Magazine - September 2014 - Cover3
IEEE Electrification Magazine - September 2014 - Cover4
https://www.nxtbook.com/nxtbooks/pes/electrification_december2022
https://www.nxtbook.com/nxtbooks/pes/electrification_september2022
https://www.nxtbook.com/nxtbooks/pes/electrification_june2022
https://www.nxtbook.com/nxtbooks/pes/electrification_march2022
https://www.nxtbook.com/nxtbooks/pes/electrification_december2021
https://www.nxtbook.com/nxtbooks/pes/electrification_september2021
https://www.nxtbook.com/nxtbooks/pes/electrification_june2021
https://www.nxtbook.com/nxtbooks/pes/electrification_march2021
https://www.nxtbook.com/nxtbooks/pes/electrification_december2020
https://www.nxtbook.com/nxtbooks/pes/electrification_september2020
https://www.nxtbook.com/nxtbooks/pes/electrification_june2020
https://www.nxtbook.com/nxtbooks/pes/electrification_march2020
https://www.nxtbook.com/nxtbooks/pes/electrification_december2019
https://www.nxtbook.com/nxtbooks/pes/electrification_september2019
https://www.nxtbook.com/nxtbooks/pes/electrification_june2019
https://www.nxtbook.com/nxtbooks/pes/electrification_march2019
https://www.nxtbook.com/nxtbooks/pes/electrification_december2018
https://www.nxtbook.com/nxtbooks/pes/electrification_september2018
https://www.nxtbook.com/nxtbooks/pes/electrification_june2018
https://www.nxtbook.com/nxtbooks/pes/electrification_december2017
https://www.nxtbook.com/nxtbooks/pes/electrification_september2017
https://www.nxtbook.com/nxtbooks/pes/electrification_march2018
https://www.nxtbook.com/nxtbooks/pes/electrification_june2017
https://www.nxtbook.com/nxtbooks/pes/electrification_march2017
https://www.nxtbook.com/nxtbooks/pes/electrification_june2016
https://www.nxtbook.com/nxtbooks/pes/electrification_december2016
https://www.nxtbook.com/nxtbooks/pes/electrification_september2016
https://www.nxtbook.com/nxtbooks/pes/electrification_december2015
https://www.nxtbook.com/nxtbooks/pes/electrification_march2016
https://www.nxtbook.com/nxtbooks/pes/electrification_march2015
https://www.nxtbook.com/nxtbooks/pes/electrification_june2015
https://www.nxtbook.com/nxtbooks/pes/electrification_september2015
https://www.nxtbook.com/nxtbooks/pes/electrification_march2014
https://www.nxtbook.com/nxtbooks/pes/electrification_june2014
https://www.nxtbook.com/nxtbooks/pes/electrification_september2014
https://www.nxtbook.com/nxtbooks/pes/electrification_december2014
https://www.nxtbook.com/nxtbooks/pes/electrification_december2013
https://www.nxtbook.com/nxtbooks/pes/electrification_september2013
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